In Johannesburg, South Africa, the South West Township (Soweto) was one of several areas established early in the last century f
or blacks to live away from the white ruling minority. On the hills surrounding Soweto, the company that provides South Africa's electricity, Eskom, built a large coal-burning power plant. The electricity was for white areas of Johannesburg, miles away from the plant, and the residents of Soweto had no electrical connections. The major long-term global problem with using coal to generate electricity is the ________.